This invention relates to an excessive idle termination system for use in motor vehicles.
Common to these systems is the objective of shutting down the engine upon an excessive idle condition so as to thereby conserve fuel and avoid needless operation of the engine. The systems sense one or more input conditions which are indicative of an idle condition and when a sensed condition has existed for a predetermined interval without correction, the system operates to interrupt the ignition circuit thereby shutting down the engine. Various types of warning systems may also be utilized in conjunction with the basic ignition interrupt system to alert the operator to an impending shutdown unless the condition which gave rise to idle indication abates. One typical input condition which is sensed to indicate an excess idle condition is the duration for which the operator's seat is left unoccupied while the engine is running. For example, in the case of a delivery vehicle where the operator is required to leave the vehicle for performing a delivery function, he may leave the vehicle in idle with the engine running. Upon his departure from the seat, the system detects the condition of unoccupiedness of the seat and commences a timing function which if, the seat is not reoccupied within the duration of the timing function, will interrupt the ignition circuit and hence cause the engine to be shut down. An example of such a prior art type of system is disclosed in U.S. Pat. No. 3,500,946 wherein a seat switch is connected as an input to a time delay relay with the time delay relay commencing its timing function upon the seat becoming unoccupied and the relay timing out if the seat is not reoccupied during the time delay period to thereby interrupt the ignition circuit and shut down the engine.
The present invention is directed to a new and improved excessive idle termination system which comprises novel and unique features. Particularly, the preferred embodiment of the invention contemplates an electronic excessive idle termination unit which is readily installable in existing automotive type vehicles either as original equipment or as an after-market accessory. One feature of the present invention is that the excessive idle termination unit is readily adaptable to accept different configurations of sensed input conditions. Another feature is that it may be employed in conjunction with different types of warning devices to alert the operator to the imminent shut down of the engine before such shut down actually occurs thereby allowing the operator time to correct the condition which gave rise to the actuation of the unit. Compactness of package size and reliability are benefits of electronic circuit construction.
Among the possible sensed input conditions are: seat occupancy vs. seat unoccupiedness; actuation of the emergency brake vs. release of the emergency brake; and engagement of the transmission vs. disengagement of the transmission. It may be desirable to override the system in certain instances, and therefore provision is made to allow for such override features to be incorporated. Specifically, it may be desirable to override the system when the hood is opened for servicing the engine compartment and the unit is adapted to accept a hood override switch which, when actuated by the opening of the hood, prevents the ignition from being cut off by the unit. There is also the possibility of a temperature override wherein the unit is precluded from shutting down the engine unless the engine has warmed up.
The foregoing features, advantages and benefits of the invention, along with additional ones, will be seen in the ensuing description and claims which should be considered in conjunction with the accompanying drawing.